From the pattern: "My own pattern uses stretchy Cascade “Fixation” yarn, so exact sizing isn’t as critical as usual sock knitting either.  And, “Fixation” is a thicker yarn than most sock yarn, so the knitting is fast and easy.  I use less than half a skein for each pair, making this project VERY economical (less than $3 and 2 hours work).  The cotton yarn is perfect for flip flop weather, especially as the mercury rises and wool becomes unthinkable."